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Memory Testing Tips for Techs

Your client brings in a machine that is acting oddly. Certain applications either won’t run or they constantly crash, especially memory intensive ones. It reboots at seemingly random moments, with the ‘recovered from a serious error’ message. Often, the machine will just go into a boot loop.

The infamous Blue Screen of Death may also make an appearance. These may not be the only symptoms, but such odd behavior often indicates that the memory is either faulty or is failing completely. There are more than a few ways to test memory sticks, and some tests are more exhaustive than others. Here are some basic tips for testing memory or troubleshooting when you believe the issue is with memory or the memory slots themselves.

1. Check Connection and Contacts

First, you’ll probably be checking the memory slots, making sure the memory is completely seated in the slots. You might consider pulling them out, carefully, one by one, checking to see if there’s any dust or obstructions that are preventing the memory from making contact in the slot as it should. It’s rare, but troubleshooting devices is all about the process of elimination. You’ll often end up kicking yourself when you skip steps and then have to backtrack to discover it was a very basic contact issue.

You might even discover that one of the memory slots was loose, and that the problem was not with the memory itself, and in that case, your search is over and you can start working with the actual problem. However, if everything looks sturdy and there is no issue with contacts or loose hardware, you’ll need to keep looking. Let’s look at some memory testing utilities.

2. Memory Testing Utilities

There are many memory testing applications, and many ways to access them. For instance, the Windows Boot Manager is one way to access the built-in memory diagnostic tool in Windows operating systems. You can also access it from inside the System Recovery Options. Finally, you can also access it by using mdsched, which schedules a memory test upon reboot. You can view the results in the Event Viewer. However, this isn’t the only way to test memory, and I actually recommend Memtest for this instead.

Memtest86 is a diagnostic memory testing utility developed by Chris Brady, and the Memtest86+ utility, created by Samuel Demeulemeester, supports newer hardware, so that’s where you’ll want to start. There are multiple ways of accessing this tool. For instance, both Knoppix and Ubuntu Live CD images, which can be booted from a handy USB thumb drive, contain a menu item in the boot menu for Memtest.

Some repair discs such as the Ultimate Boot CD also contain Memtest86 and Memtest86+. If you don’t already have a bootable live cd image of either operating system or a rescue boot cd, now would be a good time to get one. They’re highly useful for many other diagnostic tasks on machines. You can also create a bootable USB drive with just Memtest on it.

If you haven’t read it yet, I advise running over to the Memtest website, where you can read about memory testing, and why Memtest is a better solution than BIOS based memory tests. For instance, when you’re dealing with a hard memory failure, it may be obvious from simpler diagnostics, but when you have intermittent failures, Memtest will detect them.

You can also read over how the testing method works, and how Memtest algorithms can test on different layouts, and different chip types from different manufacturers. The maintenance of the project was taken over by PassMark software early this year, and you can obtain physical media containing the Memtest boot image for purchase on the site as well.

There are some cautions to use when running Memtest, however. An indication of faulty memory may not always indicate that it is definitely faulty. If memory is run at speeds that exceed its capability, you’ll see errors as well, so it’s just something to keep in mind. Also, some recommend running tests on one individual stick at a time instead of running the test with all slots taken by memory sticks.

While this can help you narrow down which stick or sticks is causing the problem, I recommend running the test first with all memory sticks in the slots. The reason for this is that occasionally individual sticks will appear fine when testing them individually, but when running the test with all sticks in the slots, the errors will show up. You might see the same issue when testing the other way around.

For example, no errors will occur when testing with all slots taken by memory sticks, but upon testing them individually, errors will show up. At least if you start out by testing them all at once, you’ll have a better idea of which direction to go, rather than spending time on 2 or 3 other sticks that checked out fine before you finally get to the last stick which ended up being faulty.

If you haven’t done one of these tests before, be prepared for a long wait. Sometimes it could be as long as 10 hours before faulty memory is discovered, and sometimes it can be discovered within a much shorter time period. If you have some good memory available for testing, you might try the next option, but if you’re waiting on an order for more memory sticks, you might as well start the elimination test.

3. Replacement Sticks

Many shops, perhaps yours included, keep a stash of old and new memory sticks, often enough to use as a simple memory test. Simply swapping out the existing memory with what you have on hand, when you know for a certainty that your memory is good, is also a good way to check for bad memory. It’s also a good way to discover when a slot may be failing, as your memory sticks that you know to be good will still fail in a bad slot.

This is actually a good reason to keep a sufficient supply of popular memory sticks on hand rather than needing a day to run memory tests on the bench, if it will take that long to run Memtest on the memory in the machine. However, if you just ran out of memory sticks or if you just need the utility to run as printable proof that the memory showed up faulty, at least you have several ways of testing it using utilities.

If the memory tests out fine, that means more diagnostics are in order, but that’s a topic for another day. If you have an odd experience with memory failure, or a good experience with a certain utility, drop a comment below, we would love to hear it!